Steam or hot-water boiler

ABSTRACT

In a steam or hot-water boiler of the type, which consists of a radiant heat combustion chamber and at least one convection part connected directly thereto, the end plate of the convection part turned towards to the combustion chamber will be intensely heated. In order to ensure that this plate is efficiently cooled one baffle plate within the water space of the convection part is more closely placed with respect to the end plate than the ordinary spacing between the baffle plates, in such a manner that an increased velocity of the waterflow is obtained, which means a higher rate of heat transfer and also a safe removal of possible steam bubbles from the inside of the end plate.

1| United States Patent [151 3,638,620 Ostbo 1 Feb. 1, 1972 [54] STEAM 0R HOT-WATER BOILER 2,388,647 11/1945 Sawyer ..122/l26 1,658,819 21928 U bl ....l22115 [721 invent Nils Amb-lm 05m, Cmebmg, 681,244 81901 ..122i11s Sweden Prima Examinerl(enneth W. Sprague [73] Assignee. Gotaverkem Angteknlska AB (Gotaverken ry Heat Engineering Co. um) Goteborg, Attorney-Plerce, Schefi'ler & Parker Swede 57 ABSTRACT [22] Filed: 1970 In a steam or hot-water boiler of the type, which consists of a [21] Appl. No.: 25,623 radiant heat combustion chamber and at least one convection part connected directly thereto, the end plate of the convection part turned towards to the combustion chamber will be 1 Forelg" Apphcmlon y Data intensely heated. In order to ensure that this plate is efficiently Apr: 23, 1969 Sweden .575 6/69 baffle Plate within tion part 18 more closely placed with respect to the end plate than the ordinary spacing between the baffle plates, in such a [52] {1.8. CI ..l22/115, 122/130 manner that an increased velocity of the waterflow is [5 1 Cl 9/04 tained, which means a higher rate of heat transfer and also a [58] Field of Search ..l22/ 1 14-130 f removal f Possible Steam bubbles f the inside f the end plate. [56] References Cited 2 Claims, 1 Drawing Figure UNITED STATES PATENTS 989,270 4/1911 Lester et al. ..1 22/123 X g I i I 11 i 9 l i i;

1 i J a u I I n I l n 19 n I nu STEAM OR HOT-WATER BOILER BACKGROUND OF THE INVENTION The present invention refers to a steam or hot-water boiler provided with a radiant heat combustion chamber and at least one convection part arranged as an axial elongation of said chamber and designed as a heat exchanger containing a number offire tubes fitted between two end plates.

SUMMARY OF THE INVENTION The aim of the invention is to design the components of the boiler to obtain an efficient cooling of that end plate of the convection part, which is turned towards the combustion chamber. The convection part is designed as fire tube boiler, where the passage of water outside the tubes is governed by means of baffle plates arranged parallel to the end plates, and the invention is characterized by the distance between the end plate turned towards the chamber and the baffle plate adjacent this end plate being noticeably smaller than the mutual distance between any two adjacent baffle plates.

BRIEF DESCRIPTION OF THE DRAWING One embodiment of the invention is shown on the accompanying drawing as utilized in a vertical cylindrical hot-water boiler with a central furnace and two convection parts.

DESCRIPTION OF THE PREFERRED EMBODIMENT The boiler is provided with a cylindrical combustion chamber 10, or furnace, and a convection part located at each end of the furnace, said convection parts being generally denoted by 11 and 12. Three oil or gas burners 13 are mounted in the wall of the furnace and are directed tangentially with respect thereto in such a manner that the gases will obtain a rotating movement within the furnace. The combustion gases will escape from the furnace through the fire tubes 14 of the convention parts, and will reach chambers 15 and 16 at the outward ends of the convection parts. These chambers are connected to a flue or funnel. Water is supplied through a connection 17 at the lower end of the boiler and will leave the boiler through a connection 18 at the upper end of the boiler.

Each convection part consists of a cylindrical shell 19 and two end plates 20 and 21 respectively. The fire tubes 14 are connected to the end plates by welding, or by their ends being expanded into bores in said plates. The fire tubes will act as strengthening members for the end plates. The water chamber within each convection part is subdivided into a number of passages by means of baffle plates 22 and 23 which, as represented in the drawing, are disposed with staggered openings providing a labyrinthine heat-exchange space for flow of water forwards and backwards over fire tubes 14. The

baffle plate 23, which is fitted adjacent to the end plate 20 turned towards the furnace, is located noticeably closer to that end plate than the distance between any two adjacent baffle plates in the remainder of the convection part. The velocity of the water within the passage formed between the end plate and the pertaining baffle plate will thereby be considerably increased, which is advantageous with respect to the heat transfer. Simultaneously any possible steam bubbles, which may have been formed along the end plate, will be carried away by the stream of water towards the outlet.

The furnace 10 is surrounded by water tubes 24. These are preferably provided with flanges and are welded together in such a manner that the gastight wall is formed. These water tubes are connected to the end plate 20 outside the fire tubes and an efficient water circulation is thereby guaranteed.

The invention may also be utilized with boilers having a single convection part only. On such an occasion the furnace preferably is mounted in the top part of the boiler. With the arrangement for mounting the burners shown on the drawing it is possible to substitute the upper convection part with an end portion having twin walls but lacking fire tubes The boiler may also be mounted with its longitudinal axis horizontal, and

if it is to be used as a steam boiler, a steam drum has to be fitted at outlet 18.

What I claim is:

1. In a boiler having a radiant heat combustion chamber and at least one convection part arranged as an axial elongation of said combustion chamber and designed as a heat exchanger containing a number of fire tubes fitted between a first end plate immediately adjacent said combustion chamber and a second end plate remote from said combustion chamber, a number of spaced baffle plates arranged within said convection part parallel to said end plates said baffle plates having staggered openings providing a labyrinthine heat-exchange space for flow of water forwards and backwards transversely over said fire tubes, the distance between said first end plate and the baffle plate nearest thereto being substantially smaller than is the mutual distance between any two adjacent baffle plates within the convection part, whereby flow velocity in the space between said first end plate and its next adjacent baffle plate will be substantially increased over the flow velocity between any two adjacent baffle plates.

2. The boiler defined in claim I, in which the combustion chamber is disposed between two opposite and mainly uniform convection parts each of which constitutes a heat exchanger, said boiler further comprising water inlet means adjacent the remote end plate of one convection part and water outlet means adjacent the corresponding end plate of the other convection part, and a plurality of water tubes communicating between the two convection parts and within and adjacent to the periphery of said combustion chamber forming a substantially gastight wall. 

1. In a boiler having a radiant heat combustion chamber and at least one convection part arranged as an axial elongation of said combustion chamber and designed as a heat exchanger containing a number of fire tubes fitted between a first end plate immediately adjacent said combustion chamber and a second end plate remote from said combustion chamber, a number of spaced baffle plates arranged within said convection part parallel to said end plates said baffle plates having staggered openings providing a labyrinthine heat-exchange space for flow of water forwards and backwards transversely over said fire tubes, the distance between said first end plate and the baffle plate nearest thereto being substantially smaller than is the mutual distance between any two adjacent baffle plates within the convection part, whereby flow velocity in the space between said first end plate and its next adjacent baffle plate will be substantially increased over the flow velocity between any two adjacent baffle plates.
 2. The boiler defined in claim 1, in which the combustion chamber is disposed between two opposite and mainly uniform convection parts each of which constitutes a heat exchanger, said boiler further comprising water inlet means adjacent the remote end plate of one convection part and water outlet means adjacent the corresponding end plate of the other convection part, and a plurality of water tubes communicating between the two convection parts and within and adjacent to the periphery of said combustion chamber forming a substantially gastight wall. 